I agree with the comment that ample training should be needed to carry a firearm, wether it be Conceal or Open Carry. But I disagree that a handgun safety course would suffice in this training. I've seen people come out of the safety course not even knowing how to unload a gun or that could properly cock a handgun.
Carrying, IMO, is a huge responsibility and much like being a Pilot, not only should you have the proper training, but also in some way should need to show a history of courses/training completed and time logged both going through training in stress situations, shooting, and handling that SPECIFIC firearm that you will carry. There are people who are willing to take on the responsibility and others who aren't. I for one, think, that for myself, the risk and responsibility of carrying greatly outweigh the probability that shit will happen and I will actually need to use one of my firearms.
While this won't stop criminals from doing whatever they want. I doubt a beginner (myself included) should a situation arise, react reasonably and properly, in the proper mindset, trying to stop some whack job that has a gun and shooting up the place. I can see instances where more harm then good would ensue.
As you all saw these crazy guys getting their gun jammed trying to kill people (Oregon and that political one in Europe) got the crap kicked out of them because their weapons failed and it wasnt second nature to them to clear the jam and proceed (in this instance good) but imagine that happening to a good guy whom was trying to stop a crazy who hasnt shot anyone? After than instance the crazy would panic and bullets will fly ultimately injuring and killing people who may have been better off in the first place and possibly giving the crazy yet one more loaded weapon.
I speak for only myself in saying this (and you can call me a pussy if you want) but I for one am not sure that i could shoot or kill someone. I know both military and police who also aren't sure that they could do this either and some of them are marines who are trained to kill!.
In summary, I believe there are non military, non leo citizens out there who should, are trained for, and are mentally equipped, to carry. But to give someone that responsibility, whom isnt trained, whether they want to carry or not, could make a bad situation worse.